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A better way to do lighting in Cycles is to use emission planes. First, add a plane with Shift + A > Mesh > Plane. Then, rotate the plane to face a significant point in your scene or at your object:



Next, add an emission material to the plane by going under the Material tab and clicking New. Set the material's Surface to Emission and give it a Strength of at least 15 or so.



You can use as many of these planes as you want, but try to add only as many lights as you would need in the real world.